Last spring was cool and wet, and rangelands in Lemhi County were a sea of blue lupine.
Consequently, many “crooked calves” were born on area ranches this spring — the result of toxic alkaloids in the native wildflower, ingested by pregnant cows at some point between 40 and 100 days’ gestation, causing malformations in the developing fetus.
Detrimental effects are usually in leg joints, but occasionally a calf is born with a cleft palate.
At birth, the calf may be unable to straighten crooked limbs enough to enter the birth canal. Sometimes the twisted calf must be surgically removed by C-section.
Dr. Robert Cope, a Salmon veterinarian, has seen many crooked calves and other birth defects caused by lupine in his 45 years of practice. He believes schistosomus reflexus, a condition in which calves are born with internal organs outside of the body, may also be caused by lupine.
“The fetus is formed in reverse; instead of having the back arched, it’s folded the other way, with all four feet and the head pointed one direction and the guts hanging out the other side,” Cope said.
Cope knows of a rancher near Leadore who blamed lupine for causing the condition in his calves.
“When he was ranching in northwestern Montana, in 1981 there many cases following Mount St. Helens eruption in 1980,” Cope said. “When ranchers turned cattle out on the range that year the ash was so thick the only plants sticking up through it were lupine. That next spring they had a lot of deformed calves.”
Lupine remains toxic all summer, but negative health effects don’t seem to surface in cows exposed further than three months into their pregnancy.
“The only way you can avoid this problem is not turn them out so soon (wait until they are past 100 days pregnant), or breed earlier, so they are past that stage of gestation when they go to the range,” he said.
This would mean holding April-May bred cows — calved from January through February — off mountain pastures until late July or August, or calving in the fall and breeding in December. Lupine can be safely grazed by at-risk, pregnant cattle after the pods have released their seeds, which occurs during mid- to late summer.
Some ranchers are considering fall calving to avoid the problem and hope they can work out a change of timing on their use of Bureau of Land Management allotments. There’s no way to get rid of lupine because it is a hardy native plant, growing nearly everywhere.
Dan and Eileen French, who ranch near Salmon, have endured their worst year ever for crooked calves.
“Last year we had 50 young cows on summer range in Mulkey Creek, and out of that group we’ve had 26 lupine calves,” Dan French said. “Lupine is also spreading into a lower pasture where our older cows were last summer, and we had seven lupine calves from those cows. In previous years, we’ve only had a few cases.”
Calves that survive birth have varying degrees of deformity. The Frenches are feeding six calves on bottles because they are too deformed to stand up to suckle a cow. The other calves, with their moms, will stay home on pasture because they can’t travel well enough to go to the mountains.
A few years ago a company was selling a new type of mineral and claimed it would prevent problems because it contained bentonite, ostensibly to bond with the toxin in the cow’s stomach enabling it to pass through the digestive tract without being absorbed.
“Instructions were to feed it for two months before cows went to the range and then feed it out there. That company finally got it sweet enough the cows ate it, but they wouldn’t eat it out on the range,” said Dan French.
Kyle Bird, who ranches on McDevitt Creek in the upper Lemhi Valley, always has a dozen or more lupine calves each spring in his herd of 600 cows.
“Not all lupine calves are a total loss. Some are just a little crooked and can walk around and straighten up over time,” Bird said. “But there are always some we have to shoot when they’re born because they’ll never stand up. This year we had to shoot five,” he explained.
A couple calves had necks kinked to the side. One was so bad it had to be shot.
“When he walked, he just walked in a circle and his back was crooked. The other one wasn’t that bad. He still runs a little funny but he’s out playing with the other calves and doing OK,” Bird said. “We had some calves with lower leg and hoof turned sideways.
“When the calf tried to put weight on it, that leg would just buckle sideways. We tried splints, but the tendon is abnormal, too, and the leg won’t straighten. Over the years, the ones that are able to walk, we just grow them up to butcher. We have a big enough family we can always use the meat, but we’d rather they were normal so we could sell them.”
Occasionally a calf is born with a cleft palate. The condition is caused by a mother cow eating lupine during 55 to 60 days’ gestation, when the palate plates are forming. If the tongue is immobile (due to sedating effects of the lupine) and in the way, those plates can’t come together and the calf has a hole in the roof of the mouth.
“We haven’t had one of those, but we try to keep track of various deformities and date them to try to figure out when we’re having the most lupine problems — but with that big of a window (first 100 days) of gestation, it covers most of our summer pasture. That makes it hard to know what’s actually happening,” Bird said.
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